Highly Robust Rhenium(I) Bipyridyl Complexes Containing Dipyrromethene‐BF<sub>2</sub> Chromophores for Visible Light‐Driven CO<sub>2</sub> Reduction
Liqi Qiu, Zhi‐Wen Yang, Xiangyang Yao, Xiaoyang Li, Liang‐Nian He
Abstract
Abstract New rhenium bipyridyl complexes with dipyrromethene‐BF 2 chromophores (A‐ReBDP‐CZ, A‐ReBDP 2 , ReBDP‐CZ, and ReBDP 2 ) were developed for highly efficient photocatalytic carbon dioxide (CO 2 ) reduction to carbon monoxide (CO). These catalysts consisted of two moderate electron‐deficient groups (dipyrromethene‐BF 2 , BDP) as the visible‐light‐harvesting antenna as well as both electron donor ( N ‐phenylcarbazole, CZ) and acceptor (BDP) on Re bipyridyl framework. Among ReBDP‐CZ and ReBDP 2 complexes, the ReBDP 2 incorporating two electron‐deficient BDP chromophores had a longer‐lived photoexcited state (182.4 μs) and a twofold enhanced molar absorption coefficient ( ϵ =157000 m −1 cm −1 ) compared with ReBDP‐CZ. Thus, ReBDP 2 achieved the superior photocatalytic reactivity and stability with a CO turnover number (TON CO ) value as high as 1323 and quantum yield ( Φ CO ) up to 55 %, which was the most excellent photocatalysis efficiency among the single‐active‐site Re catalysts without additional photosensitizer. Furthermore, the acetylene‐bridged linker was detrimental to the photoactivity and durability of the catalyst. In brief, two BDP‐based Re bipyridyl systems with outstanding catalytic performance and significant visible‐light‐harvesting capabilities in the solar spectrum offer a promising strategy for solar‐to‐fuel conversion schemes.